Michael Bacarella <[EMAIL PROTECTED]> wrote:
> How to reproduce:
>
> 1. Run md5sum interactively. Make sure you're using textutils
> md5sum, some GNU/Linux distributions (like Debian) have their own
> md5sum and rename the one from textutils to something like md5sum.textutils.
> $ md5sum
>
> 2. Type one line of text into md5sum, then hit CR. "foobar" works.
> $ md5sum
> foobar
>
> 3. Now hit EOF. Nothing should happen (the bug)
> $ md5sum
> foobar
>
> 4. Hit EOF again. Now it should exit.
> $ md5sum
> foobar
> 14758f1afd44c09b7992073ccf00b43d -
> $
Thank you for the fine report and patches.
I've applied your cksum patch.
I chose to make a more invasive (but functionally equivalent)
change to md5.c and sha.c.
* md5.c (md5_stream) [BLOCKSIZE]: Move definition to top of file.
Ensure that it is a multiple of 64.
Rearrange loop exit tests so as to avoid performing an
additional fread after encountering an error or EOF.
* sha.c (sha_stream): Likewise.
Reported by Michael Bacarella.
Index: md5.c
===================================================================
RCS file: /fetish/cu/lib/md5.c,v
retrieving revision 1.13
retrieving revision 1.14
diff -u -p -u -r1.13 -r1.14
--- md5.c 17 Nov 2001 13:29:42 -0000 1.13
+++ md5.c 18 Feb 2003 19:00:16 -0000 1.14
@@ -52,6 +52,12 @@
# define SWAP(n) (n)
#endif
+#define BLOCKSIZE 4096
+/* Ensure that BLOCKSIZE is a multiple of 64. */
+#if BLOCKSIZE % 64 != 0
+/* FIXME-someday (soon?): use #error instead of this kludge. */
+"invalid BLOCKSIZE"
+#endif
/* This array contains the bytes used to pad the buffer to the next
64-byte boundary. (RFC 1321, 3.1: Step 1) */
@@ -132,8 +138,6 @@ md5_stream (stream, resblock)
FILE *stream;
void *resblock;
{
- /* Important: BLOCKSIZE must be a multiple of 64. */
-#define BLOCKSIZE 4096
struct md5_ctx ctx;
char buffer[BLOCKSIZE + 72];
size_t sum;
@@ -151,19 +155,31 @@ md5_stream (stream, resblock)
sum = 0;
/* Read block. Take care for partial reads. */
- do
+ while (1)
{
n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
sum += n;
+
+ if (sum == BLOCKSIZE)
+ break;
+
+ if (n == 0)
+ {
+ /* Check for the error flag IFF N == 0, so that we don't
+ exit the loop after a partial read due to e.g., EAGAIN
+ or EWOULDBLOCK. */
+ if (ferror (stream))
+ return 1;
+ goto process_partial_block;
+ }
+
+ /* We've read at least one byte, so ignore errors. But always
+ check for EOF, since feof may be true even though N > 0.
+ Otherwise, we could end up calling fread after EOF. */
+ if (feof (stream))
+ goto process_partial_block;
}
- while (sum < BLOCKSIZE && n != 0);
- if (n == 0 && ferror (stream))
- return 1;
-
- /* If end of file is reached, end the loop. */
- if (n == 0)
- break;
/* Process buffer with BLOCKSIZE bytes. Note that
BLOCKSIZE % 64 == 0
@@ -171,7 +187,9 @@ md5_stream (stream, resblock)
md5_process_block (buffer, BLOCKSIZE, &ctx);
}
- /* Add the last bytes if necessary. */
+ process_partial_block:;
+
+ /* Process any remaining bytes. */
if (sum > 0)
md5_process_bytes (buffer, sum, &ctx);
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